You have to choose between lace and ` skin` [ polyurethane] bases.
It`s a trade-off... lace is by far the best for ` breatheability` .... by doing a perimeter-only bond [rather than glue all over the scalp], you allow 90% of the covered-area to breath ...moisture can evaporate off, and heat escapes normally too [we lose most of our body heat through the scalp]...you can shower /allow water at your system, thus helping to dilute /wash off sweat etc. Ideally though, in order to properly clean your head,and remove oils, remove the system and shampoo your head in the normal way...... the area which has had the bonding-materials on it needs to be regularly cleaned...sweat, oils and dead skin cells gets trapped under any adhesive material...leaving a bond in place for too long is asking for trouble ...skin-irritations and possible infection can occur ..best to avoid problems by debonding regularly.... also, if you can leave the system off one night a week or so, it`s good for the skin.
All-poly systems ......well, with an active lifestyle, my opinion is they can be a lot more work....your scalp /pores can`t breath and sweat etc. has no place to go.....you also have to do an all-over [glued] bond with them usually because otherwise air will be trapped under it and is detectable to touch as it`s a bit like a balloon..... it`s harder to remove a poly system too ..you have to begin at the edge/s [ with lace-release to break down the bond] and gradually peel it back...the upside is residue is easier to clean off of poly....it`s also more robust than lace...the hair will usually ` fail` before the poly does.... acids in sweat will eventually weaken /affect poly too and you get holes appearing in it, but that would be after much wear.French lace will also last quite well ..it`s not going to disintegrate within 3 or 4 weeks !
French lace is stronger than Swiss, for your active lifestyle/ exercise .... it`s only marginally ` thicker` or ` heavier ` [ I wear it always] and will withstand much ` abuse`....your main concern is to get the correct glue /tape which will cope with a lot of sweating..... for me, tapes are easier to work with...you can apply them directly to the lace or poly base and ` see` where you are placing them...there`s also less ` mess` when cleaning /removing...... you can apply glue directly to poly, but NEVER should you apply glue directly to lace...it will seep through onto the hair and solidify into clumps ...just don`t go there !!
You could also consider a poly perimeter and French lace base .... only issue can be hair is injected into poly and tied-in by hand onto lace ..there can therefore be a ` conflict` with the angle the hair lies in between one material and the other .... I`ve worn a poly-perimeter system many times in my Topper-wearing days and it was never an issue for me.
As for your density ... just send plenty photos to John --he`ll forward them to the factory ---- he`ll have the best idea of what to order for you...you want something ` north` of light but not actually medium, from what I can see.....you`ll have a graduated -front too [lighter density at the front hairline area, gradually increasing as you goo ` back` ]
As long as your template reflects your natural hairline around the temples etc. you should be fine..... I know this is a daunting prospect, but just having the correct research done, and also a good supply of products both for bonding and maintaining will make this a lot easier. It`s a steep learning-curve at the start for most people.